The tension and height of a sports net can affect players to a great degree. This is because the net's height and tension determines the strategy of the players. Having a very taut net can decrease the probability of the ball going over the net when it is spiked. A taut net is not so crucial because it has equal effects on both sides, while a slack net line can cause great disadvantages to the defending side and tremendous advantage to the attacking side. Therefore the net height and hence net tension must be maintained constant and to an official specification.
Keeping the net height constant is vital both in practice and competition because athletes will adapt their technique and playing style according to the conditions of the training and competition grounds. Therefore all measurements especially for the net must be kept constant. This will ensure maximum potential for athletes because the net's tension and height in competition will be substantially identical to practice conditions.
However, it is impossible for the net to be perfectly parallel with the court floor due to the weight of the net and the net suspension cable pulling down towards the floor. This will cause a minute downward curve, a catenary, in the net suspension cable, generally having its lowest point in the centre of the net line. Because of this curved effect, official regulation allows only certain degrees of difference between the bottom of the curve to an imaginary horizontal of the net line (an acceptable range is between 0.03-0.05 m for Sepaktakraw).
This is usually achieved by monitoring and adjusting net height repeatedly throughout a game. The process can take quite a long time as it requires the judge or referee to measure the height of the top edge of the net from the ground with a tape measure or ruler. Despite the time taken, the process is still accurate and is officially accepted. However, the measuring process is only accurate with a flat, leveled court or playing ground; therefore with sports such as beach volleyball or any other net sport played outdoors on uneven ground the degree of accuracy achieved by the current procedure and equipment decreases significantly.
Sports netting may be defined as an elongated net strung under tension between opposed uprights or posts; the netting being usually deployed to separate a court into two parts. The height and structure of the net and the supports are closely defined for many sports. For example, the Regulation of the International Sepak Takraw Federation (ISTAF) specifies:                “Net        The net shall be made of fine ordinary cord or nylon with 6 mm to 8 mm mesh. The net shall be 0.7 m in width and not shorter than 6.10 m in length and taped at 0.05 m from tape double at the top and sideline, called boundary tape.        The net shall be edged with 0.05 m tape double at the top and the bottom of the net supported by a fine ordinary cord or nylon cord that runs through the tape and strain over and flush with the top of the posts. The top of the net shall be 1.52 m (1.42 m for women) in height from the centre and 1.55 m (1.45 m for women's) at the posts.”        